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PubMed1992

Binomial sampling for pest management of stable flies (Diptera: Muscidae) that attack dairy cattle.

A binomial sampling plan for pest management of the stable fly, Stomoxys calcitrans (L.), was developed. Counts of stable flies on front legs of the same animal were independent and each leg from the same animal was considered a sample unit. The relationship between the mean number of flies per leg and the variance was determined and did not vary among farms. The relationship between the mean number of flies per leg and the proportion of legs with zero, one or less, and two or less flies (P0, P1, and P2) was determined and used as the basis of the binomial sampling plan. Predicted values of the mean number of flies per leg from P0, P1, and P2 were close to observed values of the mean number of flies per leg. Equations are presented for calculating the variance of a predicted value of the mean number of flies per leg using values of P0, P1 and P2 determined by sampling. Operating characteristic (OC) curves are also presented for determining the probability of making a treatment decision error at an economic threshold of one fly per leg (P0 = 0.47) using binomial sampling or direct counting. OC curves for binomial sampling with n = 50 legs were close to those for direct counting with n = 10 legs. Recommendations concerning the use of binomial sampling for stable flies are presented.

Animals↗
PubMed2004

Binomial sequential sampling plans for late instars of European corn borer (Lepidoptera: Crambidae), corn earworm (Lepidoptera: Noctuidae), and damaged kernels in sweet corn ears.

Late-season infestations of European corn borer, Ostrinia nubilalis (Hübner), and corn earworm, Helicoverpa zea (Boddie), were sampled to develop binomial sequential sampling plans for larval infestations and damaged kernels in sweet corn, Zea mays L., ears, near harvest. Fields were sampled to obtain a range of larval densities likely to be encountered over a range of infestation levels and field conditions. Binomial sampling plans were developed for O. nubilalis larvae, H. zea larvae, O. nubilalis, and H. zea larvae combined, and for damaged sweet corn kernels. Observed densities ranged from 0.01 to 4.40 larvae per ear for O. nubilalis, 0.005-1.62 larvae per ear for H. zea, and 0.004-36.12 damaged kernels per ear. Results of resampling analyses, based on the proportion of ears infested with one or more larvae, or damaged kernels, indicated an average sample size of 34-37 ears was necessary to classify whether larval infestations, or the incidence of damaged kernels, exceeded 5%. Two operating characteristic curves are presented for each of the four sampling plans. Initial results, with upper bounds of 0.10, and alpha (type I) and beta (type II) error rates at 0.10 and 0.05, respectively, resulted in a 90% probability of making the correct management decision at infestation levels >10%. To improve performance of the sampling plans, we modified the binomial plans by reducing the upper bound to 0.075, while maintaining the same error rates. This plan resulted in a higher probability (>95%) of making the correct management decision to reject a sweet corn load when infestation levels are >10%.

Animals↗
PubMed2006

Control decision rule for European chafer (Coleoptera: Scarabaeidae) larvae in field corn.

After greenhouse and outdoor microplot experiments, a critical density of two third instars per microplot for third instars of European chafer, Rhizotrogus (Amphimallon) majalis (Razoumowsky), in corn, Zea mays L., was derived. On average, the number of missing or damaged plants increased approximately 8% from zero to two larvae per 900 cm2. Furthermore, 23 fields in 2 yr were sampled for larvae along transects by using a golf cup cutter as the sampling tool and the critical density of 0.2 larva per sampling unit as the critical density. The sampling unit was one golf cup cutter with a diameter of 10.8 cm or 91.4 cm2 (10 sampling units approximately 900 cm2 approximately 1 foot2). Fieldwide means and variation were modeled to Taylor's power law, a = 1.42 and b = 1.47, and 20 of 23 fields fit the negative binomial probability distribution. Wald's formula for a sequential sampling plan was most accurate and least time-consuming, according to the operating characteristic and the average sample number function, relative to Iwao's and converging lines formulae. Percentage of sand, topography, soil bulk density, and proximity to trees were measured as potential predictors of areas with high larval density. Percentage of sand and soil bulk density were significant predictors, and topography and proximity to trees were not significant predictors. Field areas where the percentage of sand is high and the soil bulk density is low to moderate or where the percentage of sand is moderate and the soil bulk density is low should be chosen as sampling locations.

Animals↗
PubMed2002

Systematic sequencing of cDNA clones using the transposon Tn5.

In parallel with the production of genomic sequence data, attention is being focused on the generation of comprehensive cDNA-sequence resources. Such efforts are increasingly emphasizing the production of high-accuracy sequence corresponding to the entire insert of cDNA clones, especially those presumed to reflect the full-length mRNA. The complete sequencing of cDNA clones on a large scale presents unique challenges because of the generally small, yet heterogeneous, sizes of the cloned inserts. We have developed a strategy for high-throughput sequencing of cDNA clones using the transposon Tn5. This approach has been tailored for implementation within an existing large-scale 'shotgun-style' sequencing program, although it could be readily adapted for use in virtually any sequencing environment. In addition, we have developed a modified version of our strategy that can be applied to cDNA clones with large cloning vectors, thereby overcoming a potential limitation of transposon-based approaches. Here we describe the details of our cDNA-sequencing pipeline, including a summary of the experience in sequencing more than 4200 cDNA clones to produce more than 8 million base pairs of high-accuracy cDNA sequence. These data provide both convincing evidence that the insertion of Tn5 into cDNA clones is sufficiently random for its effective use in large-scale cDNA sequencing as well as interesting insight about the sequence context preferred for insertion by Tn5.

Base Composition↗
PubMed1992

The value of capture-recapture methods even for apparent exhaustive surveys. The need for adjustment for source of ascertainment intersection in attempted complete prevalence studies.

Almost all reported prevalence studies of which we are aware make exhaustive attempts to find diagnosed individuals and report all affected individuals, but make no attempt to estimate or adjust for missing cases. Yet very simple methods introduced in the planning stage of a prevalence study may enable investigators, or at least those subsequently reading their reports, to derive such adjusted estimates. If investigators keep track of the nature of the ascertainment of cases by source and collect and report data that allow calculation of the number of cases by source intersection, then they, or at least others, may derive estimates of missing cases and of the total population affected, by using readily available analogues of capture-recapture methods developed for wildlife populations censuses. Unfortunately, such methods are often inappropriately disparaged or ignored by epidemiologists. The derived estimates are sensitive to assumptions about dependence or independence ("interaction") of various sources, assumptions that sometimes are unprovable, and these estimates have some uncertainty because of statistical fluctuation. Moreover, most investigators who attempt exhaustive prevalence studies apparently believe that they have ascertained all cases and that there is no need to attempt to adjust for, let alone provide data pertinent to, the number of missing cases or to use a statistical method that will at best imply a certain imprecision to their result. Yet a survey that reports prevalence data without adjustment for, or data on, source intersection in essence makes an estimate of missing cases--zero--while providing no quantitative grounds for that claim. The results of all such surveys should be regarded with skepticism because, at best (if the case reports are accurate), they provide only a lower boundary of prevalence. We illustrate the grounds for these views by analyzing data from an apparently exhaustive prevalence study that used at least 14 distinct sources for ascertainment, including advertising, to find cases. Available limited data on source intersection provided in the report enable the plausible inference that the study missed about 25-40% of cases. We urge that no attempted complete prevalence studies be presented without data on ascertainment by source intersection.

Bias↗
PubMed2000

Smaller-than-expected sevoflurane concentrations using the Sevotec 5 vaporizer at low fill states and high fresh gas flows.

Smaller-than-expected concentrations of sevoflurane were delivered by Sevotec 5 vaporizers (Datex-Ohmeda, Madison, WI) at low-fill states, 8% dialed concentrations, and high fresh gas flows. Clinically, this would lead to prolonged induction times. The risk of complications from prolonged inhaled induction could be increased when using a vaporizer with these characteristics.

Anesthesia, Inhalation↗
PubMed1996

Intraoperative radio-lympho-scintigraphy improves sentinel lymph node identification for patients with melanoma.

BACKGROUND: The sentinel lymph node (SLN), the first node draining the primary tumor site, has been shown to reflect the histologic features of the remainder of the lymphatic basin in patients with melanoma. Intraoperative localization of the SLN, first proposed by Morton and colleagues, has been accomplished with the use of a vital blue dye mapping technique. Technical difficulties resulting in unsuccessful explorations have occurred in up to 20% of the dissections. OBJECTIVES: The authors aimed to define the SLN using gamma detection probe mapping and to determine whether intraoperative radiolymphoscintigraphy using technetium sulfur colloid and a hand-held gamma-detecting probe could be used to improve detection of all SLNs for patients with melanoma. METHODS: To ensure that all initial nodes draining the primary site were removed at the time of selective lymphadenectomy, the authors used intraoperative radiolymphoscintigraphy to confirm the location of the SLN, which was determined initially with the preoperative lymphoscintigram and the intraoperative vital blue dye injection. PATIENT POPULATION: The patient population consisted of 106 consecutive patients who presented with cutaneous melanomas larger than 0.75 mm in all primary site locations. RESULTS: The preoperative lymphoscintigram revealed that 22 patients had more than one lymphatic basin sampled. Two hundred SLNs and 142 neighboring non-SLNs were harvested from 129 basins in 106 patients. After the skin incision was made, the mean ratio of hot spot to background activity was 8.5:1. The mean ratio of ex vivo SLN-to-non-SLN activity for 72 patients who had SLNs harvested was 135.6:1. When correlated with the vital blue dye mapping, 139 of 200 (69.5%) SLNs demonstrated blue dye staining, whereas 167 of 200 (83.5%) SLNs were hot according to radioisotope localization. With the use of both intraoperative mapping techniques, identification of the SLN was possible for 124 of the 129 (96%) basins sampled. Micrometastases were identified in SLNs of 16 of the 106 (15%) patients by routine histologic analysis. CONCLUSION: The use of intraoperative radiolymphoscintigraphy can improve the identification of all SLNs during selective lymphadenectomy.

Adolescent↗
PubMedDate not supplied

Estimating nonfatal traumatic brain injury hospitalizations using an urban/rural index.

OBJECTIVE: To develop state-level estimates of the annual number of nonfatal cases of traumatic brain injury (TBI) resulting in hospitalization. METHODS: The estimation process incorporates annual nonfatal TBI hospitalization case counts from 15 states funded by the Centers for Disease Control and Prevention to conduct TBI surveillance; annual fatal TBI case counts based on National Center for Health Statistics data for all 50 states; and an index reflecting the urban/rural character of each state. These data are used to develop a negative binomial regression model that yields estimates of the annual number of nonfatal TBI hospitalization cases for each state not funded to conduct TBI surveillance. RESULTS: Sensitivity analysis suggests that on average the estimates fall within +/- 15% of the case counts that would be obtained directly from surveillance. CONCLUSION: In combination, the TBI case count data and the urban/rural index support effective modeling and estimation of annual nonfatal TBI hospitalization case counts at the state level.

Accidents, Traffic↗
PubMed1990

A family of mathematical models to describe the risk of infection by a sexually transmitted agent.

Several recent publications have used, without demonstrating its derivation, a mathematical model that describes the risk of being infected by a sexually transmitted agent as a function of four parameters: the number of partners, the number of contacts with each partner, the per-contact probability of transmission, and the probability of a partner being infected. The model is derived both from elementary probability concepts and, more formally, by using the binomial expansion and conditional probabilities. The assumptions involved in these derivations are brought out, as are the limitations they impose on the uses of the model. The model equations used so far in published studies are shown to be special cases of a general form that allows for more variability of the sexual behavior modeled. The different uses to which the model has been put are categorized, and some further ones are suggested.

Acquired Immunodeficiency Syndrome↗
PubMed1990

A rapidly converging algorithm for exact binomial confidence intervals about the relative risk in follow-up studies with stratified incidence-density data.

A rapidly converging algorithm is given to calculate exact confidence intervals about the adjusted relative risk in follow-up studies with stratified incidence-density data. The network approach that Mehta developed for tables with person-count numerators and denominators is adapted to tables with person-count numerators and person-time denominators. This algorithm updates an earlier program by Guess et al, yielding the same quantities but with running times that are between ten and a hundred times faster. Applications to Poisson regression are discussed.

Algorithms↗
PubMed2003

Ophthalmologic findings in patients with nonsyndromic plagiocephaly.

The purpose of this article was to study the prevalence of strabismus and astigmatism in children with nonsyndromic plagiocephaly. Children with deformational plagiocephaly do not have an increased prevalence of strabismus compared with the general population but do have an increased prevalence of astigmatism, whereas children with nonsyndromic craniosynostotic plagiocephaly have an increased prevalence of strabismus and astigmatism. This observational cohort study retrospectively reviewed patients in a multidisciplinary craniofacial clinic between 1993 and 2001. Patients were referred for evaluation and management of plagiocephaly or craniosynostosis. One hundred eleven patients had deformational plagiocephaly, and 45 had synostotic plagiocephaly. Patients with lambdoid craniosynostosis, hemifacial microsomia, any syndromic form of craniosynostosis, or without a formal diagnosis were excluded. All patients underwent detailed ophthalmologic, ocular motility, and craniofacial examinations. Diagnosis was based on clinical and radiographic findings. Patients were evaluated between birth and age 14 years (mean = 13 months; SD = 22 months). Only 1 of 111 (<1%) patients with deformational plagiocephaly had an esodeviation, and none had an exodeviation. Three of 45 patients (7%) with synostotic plagiocephaly had an exodeviation, and none had an esodeviation. Eight of 93 patients (9%) with deformational plagiocephaly had unilateral astigmatism, and 14 (15%) had bilateral astigmatism (mean = 1.82 diopters). Three of 43 patients (7%) with synostotic plagiocephaly had unilateral astigmatism, and 9 (21%) had bilateral astigmatism (mean = 1.83 diopters). Patients with deformational plagiocephaly do not appear to have a higher prevalence of horizontal strabismus than the normal population. Exotropia is more common in patients with nonsyndromic craniosynostotic plagiocephaly than in the general population. The prevalence of astigmatism in patients with nonsyndromic craniosynostotic plagiocephaly appears to be greater than in the general population, but this higher prevalence requires further study.

Adolescent↗
PubMed2002

Enhancing tactile sensation in older adults with electrical noise stimulation.

Older adults often suffer from diminished somatosensation stemming from age-related neuropathy. Recently, localized low-level electrical noise stimulation was shown to enhance tactile sensitivity in healthy young subjects. Here, we hypothesized that fine-touch sensitivity in older adults can be similarly improved. Semmes-Weinstein monofilaments were used to evaluate fine-touch sensitivity on the first metatarsal phalangeal joint with four electrical stimulus conditions and a null (no-noise) condition in nine healthy elderly subjects. Electrical noise stimulation resulted in a statistically significant increase in the number of detections below the null-condition detection threshold, for five of the nine subjects, as well as across the entire population. This work suggests that electrical noise-based techniques may enable people to overcome functional difficulties due to age-related sensory loss.

Aged↗
PubMed2004

Prevalent diagnosed HIV in England, Wales and Northern Ireland: adjusted totals 1996 to 2001 and extrapolations to 2004.

OBJECTIVE: To predict trends in diagnosed HIV prevalence by extrapolation to 2004 using data from the annual surveys of individuals receiving HIV-related care in England, Wales and Northern Ireland from 1996 to 2001. METHODS: Data from the annual surveys of prevalent HIV infections diagnosed (SOPHID) were adjusted for under-reporting and non-attendance and separately extrapolated for infections acquired homosexually, heterosexually and by other routes. The data were extrapolated using negative binomial and linear regression models based on the 1996 to 2001 annual surveys. RESULTS: The negative binomial model predicted an increase of 56% in diagnosed HIV prevalence in England, Wales and Northern Ireland between 2001 and 2004. The linear model predicted an increase of 25% for the same time period. The predicted increases are mostly driven by the large rise in the number of new diagnoses, in particular in individuals infected heterosexually. CONCLUSION: Increases in HIV prevalence in England, Wales and Northern Ireland have diverged from a linear trend. Negative binomial modelling of the data predicts that large rises in prevalence will continue during the early 2000s.

Binomial Distribution↗
PubMed2004

Nasal osteotomies: a clinical comparison of the perforating methods versus the continuous technique.

Do perforating lateral osteotomies cause less ecchymosis and edema compared with the popular continuous method? Many studies have demonstrated that perforated osteotomies cause less trauma and periosteal disruption. Numerous investigators have subjectively perceived less postoperative ecchymosis and edema, but no clinical study has compared the perforated methods versus the continuous technique in the same patient. This prospective, randomized, partially blinded study was designed to test the hypothesis that the perforating method causes less postoperative ecchymosis and edema compared with the continuous lateral osteotomy technique. The questions remain: does the type of perforating osteotomy affect the results? Does a percutaneous approach cause more ecchymosis and edema by the access maneuver of piercing the skin? The two perforating lateral nasal osteotomy techniques require the same 2-mm straight osteotome, so any genuine difference in postoperative ecchymosis or edema could only be attributed to the differing surgical approaches. Accordingly, this study also tests whether the external percutaneous perforating osteotomy causes more ecchymosis and edema than the internal transnasal perforating method. Twenty-five consecutive rhinoplasty patients (group A) requiring bilateral osteotomies (50 total lateral osteotomies) were randomized so that each patient received an internal/transnasal perforating lateral osteotomy (2-mm straight chisel) on one side and an internal/transnasal continuous osteotomy (4-mm curved, guarded osteotome) on the other. The next 25 patients studied (group B) received an external/percutaneous perforating lateral osteotomy (same 2-mm straight chisel as used in group A) on one side and the same internal/transnasal continuous osteotomy on the other. The final 25 consecutive rhinoplasty patients (group C) received an external percutaneous perforating lateral osteotomy on one side and an internal transnasal perforating lateral osteotomy on the other. The entry sites for the perforating osteotomies were either external (groups B and C) with a percutaneous skin puncture or intranasal (groups A and C) at the pyriform aperture. All 75 patients (150 total lateral osteotomies) initialed the surgical plan on the Gunter rhinoplasty worksheet, which has been approved by the Institutional Review Board of Abbott-Northwestern Hospital, Minneapolis, Minnesota (study no. 1341-1 M). All patients were evaluated for ecchymosis and edema on the left versus the right side of the face at 2 to 3, 7, and 21 days after the operation. The clinical evaluation was performed by two blinded examiners (clinic registered nurse and the patient with his or her family) and a partially blinded examiner (the surgeon, who did not refresh his memory about the randomization). To compare the two methods in each study (groups A, B, and C) for the six outcomes (edema and ecchymosis at 2 to 3, 7, and 21 days), the authors used an exact binomial test of the null hypothesis that the treatments do not differ. To compare the two methods in each study (groups A, B, and C) using all six outcomes simultaneously, the authors used a permutation test. By both testing methods, the perforating internal method was superior to the continuous technique (group A; p < 0.01 in both tests). Although the perforating external method gave better results than the continuous technique (group B) and the perforating internal method gave better results than the perforating external method (group C), neither of these differences was significant by either testing method. A lateral osteotomy technique should be precise, reproducible, and safe, and it should minimize ecchymosis and edema. Since edema and ecchymosis are comparable regardless of osteotome size, this prospective randomized study confirms the subjective clinical impression that perforating lateral osteotomies with a 2-mm straight osteotome reduce postoperative ecchymosis and edema in rhinoplasty patients compared with the continuous osteotomy (4-mm curved, guarded osteotome). These findings should encourage te the use of perforating osteotomies rather than continuous osteotomies.

Adolescent↗
PubMed2002

Tandem repeats in protein coding regions of primate genes.

Tandem repeats in GenBank primate nucleotide sequences annotated as protein coding regions are analyzed. It is found that only trinucleotide repeats show repeat enrichment well above the threshold of statistical significance. The statistics are improved by a simultaneous search for repeats on both the amino acid and nucleotide levels. The results of the analyses of natural sequences are interpreted by comparing them with the results of the computer simulation of the model dedicated to protein coding regions. According to the simulation results, a limited set of trinucleotides, that is, cgg, ccg, cag, and gaa repeats coding for polyalanine, polyglycine, polyproline, polyglutamine, and polylysine are prone to proliferation. It is also found that within the repeat regions slippage is more frequent by a factor of 10 than point mutations, whereas the ratio of silent versus recognizable point mutations is approximately the same as elsewhere in coding regions. The trinucleotide repeats cover slightly more than 0.3% of the protein coding regions of genes.

Animals↗
PubMed2003

Identification and characterization of multi-species conserved sequences.

Comparative sequence analysis has become an essential component of studies aiming to elucidate genome function. The increasing availability of genomic sequences from multiple vertebrates is creating the need for computational methods that can detect highly conserved regions in a robust fashion. Towards that end, we are developing approaches for identifying sequences that are conserved across multiple species; we call these "Multi-species Conserved Sequences" (or MCSs). Here we report two strategies for MCS identification, demonstrating their ability to detect virtually all known actively conserved sequences (specifically, coding sequences) but very little neutrally evolving sequence (specifically, ancestral repeats). Importantly, we find that a substantial fraction of the bases within MCSs (approximately 70%) resides within non-coding regions; thus, the majority of sequences conserved across multiple vertebrate species has no known function. Initial characterization of these MCSs has revealed sequences that correspond to clusters of transcription factor-binding sites, non-coding RNA transcripts, and other candidate functional elements. Finally, the ability to detect MCSs represents a valuable metric for assessing the relative contribution of a species' sequence to identifying genomic regions of interest, and our results indicate that the currently available genome sequences are insufficient for the comprehensive identification of MCSs in the human genome.

Animals↗
PubMed2004

Correlated inhibitory and excitatory inputs to the coincidence detector: analytical solution.

We present a solution for the steady-state output rate of an ideal coincidence detector receiving an arbitrary number of excitatory and inhibitory inputspike trains. All excitatory spike trains have identical binomial count distributions (which includes Poisson statistics as a special case) and arbitrary pairwise cross correlations between them. The same applies to the inhibitory inputs, and the rates and correlation functions of excitatory and inhibitory populations may be the same or different from each other. Thus, for each population independently, the correlation may range from complete independence to perfect correlation (identical processes). We find that inhibition, if made sufficiently strong, will result in an inverted U-shaped curve for the output rate of a coincidence detector as a function of input rates for the case of identical inhibitory and excitory input rates. This leads to the prediction that higher presynaptic (input) rates may lead to lower postsynaptic (output) rates where the output rate may fall faster than the inverse of the input rate, and shows some qualitative similarities to the case of purely excitatory inputs with synaptic depression. In general, we find that including inhibition invariably and significantly increases the behavioral repertoire of the coincidence detector over the case of pure excitatory input.

Action Potentials↗